Blair also said that the strengthening of the state union of Serbia-Montenegro is important for stability in the region.
In his letter of congratulations, handed over by British Ambassador to Belgrade David Gowan, Blair pledged Great Britain's support for the Serbian government's efforts to strengthen the rule of law, curb corruption and organised criminal, and reform the judiciary, police and public institutions.
The British Prime Minister also stressed that cooperation with the Hague tribunal is of high importance for Serbia-Montenegro's closer ties with the European Union.
Full implementation of UN Security Council Resolution 1244 is the international community's priority in Kosovo-Metohija, Blair said in the letter, adding that Great Britain is ready to support Serbia's democratic reforms and its accession to Euro-Atlantic structures.